The present invention relates to a voltage monitoring system, a voltage monitoring device of the voltage monitoring system, and a method of setting information in the voltage monitoring device of the voltage monitoring system. More specifically, the present invention relates to a voltage monitoring system capable of setting specific information for specifying the voltage monitoring device among a plurality of voltage monitoring devices; a voltage monitoring device of the voltage monitoring system, and a method of setting information in the voltage monitoring device of the voltage monitoring system.
An assembled battery has been widely installed in a vehicle, an electrical tool, and the likes. In the assembled battery, a plurality of secondary batteries is arranged and connected in series as a power source for driving a vehicle, an electrical tool, and the likes. When the assembled battery is installed in a hybrid motor vehicle or an electric vehicle as a power source for driving the hybrid motor vehicle or the electric vehicle, it is necessary to use the assembled battery having a large capacity. Accordingly, the assembled battery may be formed of secondary batteries in a range from a few tens to a few hundreds.
In the assembled battery, the secondary batteries may include a lithium ion battery, a lithium ion polymer secondary battery, and a nickel-hydrogen battery. In the following description, when it is not necessary to distinguish the secondary battery from other batteries such as a primary battery, the secondary battery is collectively referred to as a battery.
In general, a plurality of voltage monitoring devices is connected to a plurality of batteries of the assembled battery to be used as the drive power source, so that each of the voltage monitoring devices monitors a voltage value of each of the batteries. The voltage monitoring devices are connected in series. Further, a main device is provided for monitoring and controlling an operation of each of the voltage monitoring devices, so that the main device and the voltage monitoring devices constitute a voltage monitoring system.
FIG. 7 is a block diagram showing a conventional voltage monitoring system 100. As shown in FIG. 7, the conventional voltage monitoring system 100 includes a plurality of voltage monitoring devices 102 connected in series and a main device 104 for controlling an entire operation of the conventional voltage monitoring system 100 (refer to Patent Reference).    Patent Reference: Japanese Patent Publication No. 2009-17657
In the conventional voltage monitoring system 100, each of the voltage monitoring devices 102 includes communication terminals 106 and 108. The main device 104 is connected to the communication terminal 106, and the communication terminal 106 is connected to the communication terminal 108 of the voltage monitoring device 102 at a later stage. Accordingly, it is configured such that the main device 104 is capable of receiving and transmitting information with respect to all of the voltage monitoring devices 102 through the voltage monitoring device 102 directly connected to the main device 104.
In the conventional voltage monitoring system 100, each of the voltage monitoring devices 102 includes a control circuit 110, a voltage measurement circuit 112, and a clock generation circuit 114 connected to each other. The communication terminals 106 and 108 are separately connected to the control circuit 110. The control circuit 110 includes a CPU (Central Processing Unit), an ROM (Read Only Memory), an RAM (Random Access Memory), and a non-volatile storage medium such as an NVM (Non-Volatile Memory) for storing various types of information to be stored even after the voltage monitoring device 102 is turned off. The control circuit 110 is provided for controlling an entire operation of the voltage monitoring device 102.
In the conventional voltage monitoring system 100, the voltage measurement circuit 112 is provided for measuring a voltage of a power source according to an instruction of the control circuit 110. A plurality of batteries 118 is connected in series to constitute an assembled battery 116, and the voltage measurement circuit 112 is connected to one of the batteries 118.
More specifically, the voltage measurement circuit 112 is connected to a positive polarity terminal 118 of one of the batteries 118 through a positive polarity terminal 120 thereof. Further, the voltage measurement circuit 112 is connected to a negative polarity terminal of one of the batteries 118 through a negative polarity terminal 122 thereof. With the configuration described above, the voltage measurement circuit 112 measures a voltage of the corresponding battery 118.
In the conventional voltage monitoring system 100, the clock generation circuit 114 is provided for generating a clock signal for defining an operation timing of the control circuit 110 and the voltage measurement circuit 112. The clock generation circuit 114 is provided also for supplying the clock signal thus generated to the control circuit 110 and the voltage measurement circuit 112.
In the conventional voltage monitoring system 100, each of the voltage monitoring devices 102 further includes an ID input terminal 124 for receiving from an external device an input of specific information (referred to as an ID signal) for specifying the voltage monitoring device 102 thereof. The ID input terminal 124 is connected to the control circuit 110. When the voltage monitoring device 102 receives the ID signal from the external device through the ID input terminal 124, the ID signal is input to the control circuit 110, so that the ID signal is stored in the NVM. Accordingly, the specific ID signal is set in each of the voltage monitoring devices 102.
In the conventional voltage monitoring system 100 used for the assembled battery 116 to be installed in a motor vehicle, when the assembled battery 116 has a large capacity, it is necessary to increase the number of the batteries 118, i.e., the subject of the voltage monitoring. Accordingly, it is necessary to increase the number of the ID input terminals 124.
For example, when the conventional voltage monitoring system 100 includes 32 of the voltage monitoring devices 102 connected in series in multiple stages, each of the ID input terminals 124 is formed of cables in the number of five (a bit number). Accordingly, when a semiconductor circuit formed of a package having 30 pins to 56 pins is applied to the voltage monitoring device 102, it is difficult to apply the conventional voltage monitoring system 100 to the assembled battery 116 having a large capacity due to the restriction of the number of the ID input terminals 124.
In view of the problems described above, an object of the present invention is to provide a voltage monitoring system capable of setting specific information with respect to each of a plurality of voltage monitoring devices without disposing a special terminal in each of the voltage monitoring devices for setting the specific information. Further object of the present invention is to provide a voltage monitoring device of the voltage monitoring system and a method of setting information in the voltage monitoring device of the voltage monitoring system.
Further objects and advantages of the invention will be apparent from the following description of the invention.